The caudal mesenteric vein (syn.: common iliac, inferior colon) is the lower part of the common iliac vein, located in the pelvic cavity; at the top it passes into the superior hemorrhoidal vein, forming the terminal section of the inferior vena cava.
The mesenteric vein has a thick muscular layer and a smooth inner layer. It can be detected by palpation on the anterolateral surface on both sides of the rectum between the internal obturator vein and the sacral branches of the common hypogastric vein. Next, the vein passes through the soft tissue of the rectus muscle and is located below the external and middle rectal arteries. Between the terminal part of the coronoid process of the sacrum and the lower edge of the XII rib, it projects posteriorly. The intraperitoneal vein descends to the opening of the terminal loop of the subperitoneal iliohypogastric lymph node.